Q: A laser emits green light with a wavelength of $$515 \text{ nm}. $$What is the frequency of this light? ($$c = 3.00 \times 10^8$ \text{ m/s})$$

$$5.83 \times 10$$^{14}$$ \text{ Hz}$$

Q: An electron has a de Broglie wavelength of $$225 \text{ nm}. $$What is the speed of the electron? ($$m_e = 9.11 \times 10$$^{-31}$$ \text{ kg}$$, $$h = 6.626 \times 10$$^{-34}$$ \text{ J} \cdot \text{s})$$

$$3.22 \times 10^3$ \text{ m/s}$$

Q: What is the value of the energy for the $$n=1$$ energy level in the hydrogen atom? ($$E_n = -2.18 \times 10$$^{-18}$$ \text{ J} \frac{1}{n^2$})$$

$$-2.18 \times 10$$^{-18}$$ \text{ J}$$

Q: Which of the following is the correct formula for density?

$$\text{Density} = \frac{\text{mass}}{\text{volume}}$$

Question 1

Which of the following statements about protons, neutrons, and electrons is FALSE?

Accepted Answer

Electrons and protons have charges of the same magnitude but opposite sign.

Question 2

A sample contains 0.0200 mg of a substance. How many significant figures are in this measurement?

Accepted Answer

$$4$$

Question 3

Which of the following is a pure substance?

Accepted Answer

Aluminum

Question 4

A European car can travel 14 km for every 1 L of gas used. What is the car's gas mileage in miles per gallon? ($$1 	ext{ mile} = 1.609 	ext{ km}$$, $$1 	ext{ gal} = 3.785 	ext{ L})$$

Accepted Answer

$$37.2 	ext{ miles/gal}$$

Question 5

Which element has 53 protons, 74 neutrons, and 54 electrons?

Accepted Answer

Iodine

Question 6

Carbon has two stable isotopes: $$^{12}C (98.93$$%) and $$^{13}C (1.07$$%). What is the atomic mass for carbon that would appear on a periodic table?

Accepted Answer

$$12.01$$

Question 7

How many sulfur molecules are there in $$3.8$$ moles of sulfur dioxide, $$SO_2$$?

Accepted Answer

$$2.29 	imes 10$$^{24}$$

Question 8

Which of the following electromagnetic radiation types has the shortest wavelength?

Accepted Answer

Gamma rays

Question 9

A laser emits green light with a wavelength of $$515 	ext{ nm}. $$What is the frequency of this light? ($$c = 3.00 	imes 10^8$ 	ext{ m/s})$$

Accepted Answer

$$5.83 	imes 10$$^{14}$$ 	ext{ Hz}$$

Question 10

Which of the following best describes the difference between accuracy and precision?

Accepted Answer

Accuracy is how close measurements are to the true value; precision is how close measurements are to each other.

Question 11

An electron has a de Broglie wavelength of $$225 	ext{ nm}. $$What is the speed of the electron? ($$m_e = 9.11 	imes 10$$^{-31}$$ 	ext{ kg}$$, $$h = 6.626 	imes 10$$^{-34}$$ 	ext{ J} \cdot 	ext{s})$$

Accepted Answer

$$3.22 	imes 10^3$ 	ext{ m/s}$$

Question 12

Which quantum numbers are not allowed for an electron in an atom?

Accepted Answer

$$n=1, l=1, m_l=0, m_s=+1/2$$

Question 13

Which of the following is NOT a correct statement about isotopes?

Accepted Answer

Isotopes of an element have different atomic numbers.

Question 14

What is the charge of an ion of vanadium ($$V) $$that has 28 neutrons and 19 electrons? (Atomic number of $$V is 23)$$

Accepted Answer

$$+4$$

Question 15

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture in which the composition is uniform throughout.

Question 16

Which of the following transitions in a hydrogen atom emits the shortest wavelength of light?

Accepted Answer

$$n=2 \rightarrow n=1$$

Question 17

What is the value of the energy for the $$n=1$$ energy level in the hydrogen atom? ($$E_n = -2.18 	imes 10$$^{-18}$$ 	ext{ J} \frac{1}{n^2$})$$

Accepted Answer

$$-2.18 	imes 10$$^{-18}$$ 	ext{ J}$$

Question 18

Which of the following best describes the Bohr model of the atom?

Accepted Answer

Electrons orbit the nucleus in fixed paths with quantized energies.

Question 19

Which of the following is the correct formula for density?

Accepted Answer

$$	ext{Density} = \frac{	ext{mass}}{	ext{volume}}$$

General Chemistry Exam 1 Study Guide: Principles, Concepts, and Problem-Solving Skills

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